Cerebral blood flow in primates is increased by isoflurane over time and is decreased by nitric oxide synthase inhibition. Anesthesiology 1994 Jun;80(6):1320-7
Date
06/01/1994Pubmed ID
7516627DOI
10.1097/00000542-199406000-00020Scopus ID
2-s2.0-0028334293 (requires institutional sign-in at Scopus site) 44 CitationsAbstract
BACKGROUND: Cerebral blood flow (CBF) decreases over time in dogs and goats during volatile anesthesia. In the current study, we determined CBF during administration of isoflurane for 4 h in cynomolgus monkeys. In addition, we determined if nitric oxide (NO) contributes to cerebrovascular tone during isoflurane anesthesia by determining the CBF (microsphere) response to inhibition of NO synthase with N omega-nitro-L-arginine methyl ester (L-NAME).
METHODS: CBF was measured in five monkeys anesthetized with isoflurane (1.0% end-tidal). After 4 h of isoflurane (1.0% = 1 MAC), the effects of intravenous L-NAME (60 mg/kg over 10 min) followed by intravenous L-arginine (600 mg/kg over 10 min) on CBF were measured at constant cerebral perfusion pressure and arterial carbon dioxide tension.
RESULTS: CBF was unchanged over time (4 h) in cerebellum but increased by 50 +/- 18% in both forebrain and hindbrain (P < 0.05). CBF decreased by 41-48% (P < 0.05) 20 min after L-NAME in forebrain, cerebellum, and hindbrain, at which time brain NO synthase activity was less than 10% of baseline. Twenty minutes after L-arginine, CBF was increased in cerebellum by 32 +/- 8% and in forebrain by 41 +/- 9% (P < 0.05). The cerebral metabolic rate of oxygen consumption was unaffected by time or by L-NAME or L-arginine.
CONCLUSIONS: These data demonstrate that CBF increases over time during isoflurane anesthesia in primates. Tonic production of NO contributes to control of CBF in primates during isoflurane anesthesia. Increased CBF by L-arginine after L-NAME supports the hypothesis that L-NAME decreases CBF via a mechanism requiring NO synthesis.
Author List
McPherson RW, Kirsch JR, Tobin JR, Ghaly RF, Traystman RJMESH terms used to index this publication - Major topics in bold
Amino Acid OxidoreductasesAnimals
Arginine
Blood Pressure
Cerebrovascular Circulation
Isoflurane
Macaca fascicularis
Male
NG-Nitroarginine Methyl Ester
Nitric Oxide
Nitric Oxide Synthase
Pulmonary Gas Exchange
Thiopental
Time Factors
Vascular Resistance